package com.study.example.question;

import com.alibaba.druid.util.StringUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Question02 {

    public static void main(String[] args) throws IOException{
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        String str = input.readLine();
        System.out.println(getNumInStr(str));
    }

    private static String getNumInStr(String str) {
        if (StringUtils.isEmpty(str)){
            return "";
        }
        StringBuffer sb = new StringBuffer();
        for (char ch: str.toCharArray()) {
            if (ch >= 48 && ch <= 57){
                sb.append(ch);
            }
        }
        return sb.toString();
    }

}
